Coffee maker

ABSTRACT

A coffee maker having interchangeable carafes, a serial heating system, and a centrifugal brewing system. The coffee maker includes a glass carafe and a thermal carafe, either of which interchangeably fits within a carafe cavity. The presence of the glass carafe activates a heating element positioned under the carafe. The thermal carafe does not. The centrifugal brewing system includes a showerhead for distributing water at radially spaced locations over a rotating grounds basket. The control for the serial heating system activates and deactivates the heating element to allow for heat transfer between heated and unheated portions of the water. In an alternative embodiment including a batch water heating system, the coffee maker includes a modular distributor secured to the bottom of the water heating vessel by a hand-actuated bayonet mount for easy cleaning or replacement.

This is a divisional of application Ser. No. 09/205,463, filed Dec. 4,1998 (now U.S. Pat. No. 6,085,638.

BACKGROUND OF THE INVENTION

The present invention relates to coffee makers and, more particularly,to a countertop unit particularly suited for home and other low-volumeuse.

Counter-top coffee makers are well known in the art. Typically, a coffeemaker has a glass or plastic carafe for receiving brewed coffee, thecarafe being supported by, or resting upon, a heating element orsurface, as seen in U.S. Pat. No. D390,409 to Littman, issued Feb. 10,1998.

Sometimes a coffee maker includes a thermally insulated carafe forreceiving brewed coffee as seen in U.S. Pat. No. 5,463,932 to Olson,issued Nov. 7, 1995; however, a heating element or surface typically isnot provided in conjunction with a thermal carafe. The insulated carafeis capable of maintaining the coffee's temperature absent thisadditional heat source. The absence of the exposed heating element orsurface may be a safer alternative for certain consumers, such as thosehaving small children in the household. Additionally, consumers maytransport the insulated carafe containing coffee while maintaining thetemperature of the coffee. Unfortunately, consumers must choose betweena coffee maker with an uninsulated carafe and a coffee maker with aninsulated carafe.

Centrifugal coffee makers are also well known in the art. For example,U.S. Pat. No. 5,265,517 to Gilbert, issued Nov. 30, 1993, discloses acentrifugal coffee maker which heats the water and discharges the waterover the coffee grounds through two discharge ports locatedequidistantly from the axis of rotation. A basket containing the coffeegrounds spins as the water is discharged. The water flows through thecoffee grounds, out of the centrifugal basket, and is collected in acarafe or container. However, this design creates an annular pattern onthe grounds, failing to wet much of the grounds. This is insufficient atbest and wasteful at worst.

A second apparatus for making coffee and having a centrifugal brewingsystem is disclosed in U.S. Pat. No. 1,602,632 to Zorn, issued Oct. 12,1926. The coffee maker uses a plurality of tubes arranged in a spiral todischarge water over coffee grounds. The water is distributed in acircular pattern onto the grounds despite the more complicatedstructure, resulting in the same inefficiency and waste.

These prior centrifugal brewing systems have a significant drawback inthat often the coffee grounds in the rotating basket are not thoroughlyand evenly wetted. This may result in a weaker cup of coffee beingproduced than was anticipated relative to the amount of grounds added tothe machine. As a result, extra grounds may have to be added to create aproper strength cup of coffee, which results in wasted grounds.

A further problem encountered by centrifugal brewing systems is overflowof the grounds from the basket during brewing. As a centrifugal basketspins, the slurry of coffee grounds and water is forced against thesides of the basket from the centrifugal force. If the water is unableto exit the centrifugal basket at a sufficient rate, the slurry mixturemay overflow the basket, resulting in coffee grounds becoming mixed withthe brewed coffee and, thus, producing a cup of coffee with undesirablesediment. This problem is due, in part, to the high speed at which thebasket typically is spun. U.S. Pat. No. 5,265,517 to Gilbert, issuedNov. 30, 1993, discloses a centrifugal basket which preferably spins at280-350 rpm to force the coffee grounds and water slurry to rise alongthe interior walls of the centrifugal basket. The coffee escapes throughnarrow horizontal ports located in the middle portion of the basketwalls. The basket intentionally is designed so that the coffee exits thebasket slowly to provide sufficient contact time between the grounds andthe water; this is believed to be necessary to produce an optimum coffeeflavor. To prevent the slurry from overflowing the walls of the basket,the basket is provided with an inwardly-extending rim ring which is snapfit for removal by the user. The ring must be removed to place a coffeefilter within the basket.

To heat the brew water prior to depositing it over the coffee grounds,both centrifugal and standard brewing systems use either batch or serialheating. A batch heating system heats all of the brewing water prior tobeginning the brewing cycle (i.e. prior to depositing any of the wateron the grounds). Batch heating systems include a water heating chamberand a distributor in the bottom of the chamber for regulating the flowof the heated water out of the chamber. The water is stored and heatedin the heating chamber until it reaches a specified temperature, usually195°-205° Fahrenheit. The water is then released through the distributorto flow into the basket containing coffee grounds. The distributor isimmersed in water as it rests on the floor of the heating chamber andhas water flowing through it. Lime often accumulates on its exterior andwithin its flow holes, reducing the flow rate of the heated water; thus,the flow of water into the grounds basket is reduced, resulting in alonger brewing time. Ultimately, the distributor may be sufficientlyrestricted or even blocked so as to require replacement. Often, as apractical matter, this requires replacement of the entire coffee makerunit.

A serial heating system heats the brew water as it flows through a pipejust prior to its being distributed over the coffee grounds. This systemincludes a water flow pipe and a heating element adjacent to a portionof the flow pipe. The heating element heats the water in the adjacentportion of the flow pipe to at least 212° Fahrenheit, vaporizing thewater. The water vapor condenses as it continues past the heatingelement and is deposited into the basket containing coffee grounds. Whenthe coffee maker is initially filled with water, a portion of the wateroften flows through the flow pipe to a position downstream of theheating element. When the brewing cycle is activated, the portion ofwater adjacent the heating element is heated and vaporized. The watervapor moves downstream, pushing the portion of unheated water before it,and the unheated water is deposited over the coffee grounds. For optimalcoffee flavor, the brew water should be 195°-205° Fahrenheit when itcontacts the coffee grounds. Thus, the extraction of the coffee may beadversely affected by having insufficiently heated water used in thebrewing process.

SUMMARY OF THE INVENTION

The aforementioned problems are overcome by the present inventionwherein a coffee maker has interchangeable glass and thermal carafes, awater distribution system that disperses water more uniformly over thecoffee grounds, a rotating grounds basket that minimizes overflow of thecoffee grounds, and a serial heating system that minimizes the flow ofunheated brew water over the grounds. In an alternative embodiment, thecoffee maker includes a batch heating system allowing for easyreplacement of the distributor.

More specifically in a first aspect of the invention, the coffee makerincludes a glass carafe and a thermal carafe, both of which fitinterchangeably within the carafe cavity of the coffee maker. The coffeemaker further includes a carafe heating element or surface upon whichthe thermal and glass carafes rest when one of the carafes is inposition within the carafe cavity. A sensor or switch on the coffeemaker unit senses whether the glass carafe or the thermal carafe iswithin the cavity. When the glass carafe is within the cavity, theheating surface under the carafe is activated to maintain thetemperature of the brewed coffee. When the thermal carafe is sensedwithin the carafe cavity, the heating surface is not activated.

In a second aspect, the coffee maker includes a serial water heatingsystem that maximizes the amount of brew water that is heated in thedesired temperature range of 195°-205° Fahrenheit. The heating systemincludes a water flow pipe, a portion of which is adjacent to a heatingelement, and a control system. The heating element is activated by thecontrol system at the beginning of the brew cycle for a short time. Theheating element is then deactivated for a short time. This allows theheated portion of the brew water to transfer heat to the unheated brewwater downstream of the heating element without causing the downstreamwater to be dispersed over the coffee grounds. The control system thenre-activates the heating element for the remainder of the brewing cycle,causing vaporized and then condensed water to be driven through thesystem and deposited on the coffee grounds

In a third aspect, the coffee maker includes a showerhead for dispersingthe heated brew water over the coffee grounds at a variety of radiallydistinct locations. As disclosed, the showerhead includes a descendingtrough, the upper end of which is connected to an outflow end of thewater flow pipe. The heated brew water enters the showerhead and flowstoward its lower end. The showerhead contains several holes radiallyspaced above a centrifugal grounds basket. The heated water flowsthrough these holes and is deposited on several discrete radially spacedlocations on the coffee grounds contained in the centrifugal basket. Asthe basket spins, the water is driven by gravity and centrifugal forcesthrough the grounds, thus evenly wetting the grounds. Additionally, theshowerhead is easily accessible by a user to manually remove limeaccumulation from the trough and holes so that the flow of the brewwater is not impeded.

In a fourth aspect of the invention, an improved rotating grounds basketallows for a greater grounds capacity while producing an optimalflavored coffee using relatively low speed centrifugal extraction. Atthe lowered speed, the grounds and water slurry does not climb the wallsof the basket, thus reducing overflow of the slurry. Several relativelylarge vertical ports are positioned within the basket walls to allow thecoffee to easily escape the basket. The ports extend to the bottom ofthe basket so that the angular velocity need only be sufficient tothoroughly wet the grounds and force the slurry against the lowerportion of the basket walls. The radial dispersal of the water by theshowerhead over the grounds allows the water to initially contact alarge portion of the grounds, thus extracting a maximum of the coffeeflavor in a minimal amount of time. Thus, in the improved basket, theslurry need not climb the walls nor exit through small ports to providesufficient contact time between the water and grounds. The basket isspun relatively slowly, preferably at 100-150 rpm, so that the slurrydoes not climb the walls, and the slower speed allows for sufficientcontact time between the grounds and water prior to the coffee's exitingthe basket through the side ports.

In an alternative embodiment of this invention, the coffee maker mayhave a batch heating system in which all of the brewing water is heatedprior to beginning the brewing process. A water heating chamber holdsand heats the brew water, which is then released through a modulardistributor positioned on the bottom of the chamber. This modulardistributor may be easily removed by hand for cleaning or replacement.This overcomes the need to replace the entire coffee maker.

These and other objects, advantages, and features of the invention willbe more readily understood and appreciated by reference to the detaileddescription of the preferred embodiment and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the coffee maker;

FIG. 2 is a bottom perspective of the coffee maker with its housing andwater tank removed;

FIG. 3 is a rear view of the coffee maker with its housing removed;

FIG. 4 is a top perspective view of the coffee maker with its housingand lid removed;

FIG. 5 is a top perspective view of the coffee maker with the lid,showerhead cap and the housing removed;

FIG. 6 is a cross-sectional view of the coffee maker;

FIG. 7 is a perspective view of the centrifugal basket;

FIG. 8 is a cross-sectional view of a centrifugal basket;

FIG. 9 is an enlarged fragmentary cross-sectional view of the coffeemaker without the collection basket illustrating a drive mechanism;

FIG. 10 is an enlarged fragmentary cross-sectional view of the coffeemaker with the collection basket in place;

FIG. 11 is an overlay of the profiles of the glass and thermal carafesfor use with the coffee maker;

FIG. 12 is a cross-sectional view of the coffee maker showing the glasscarafe in the carafe cavity;

FIG. 13 is a cross-sectional view of the coffee maker showing thethermal carafe in the carafe cavity;

FIG. 14 is a schematic illustration of the control system for the carafesensor;

FIG. 15 is a perspective view of an alternative coffee maker;

FIG. 16 is a schematic illustration, partially cutaway, showing the flowof the water through the alternative coffee maker;

FIG. 17 is a right side partial cross-sectional view of the alternativecoffee maker;

FIG. 18 is a front partial cross-sectional view of the alternativecoffee maker;

FIG. 19 is an enlarged right side fragmentary cross-sectional view ofthe heating chamber and distributor of the alternative coffee maker;

FIG. 20 is an enlarged fragmentary front cross-sectional view of theheating chamber and distributor of the alternative coffee maker;

FIG. 21 is an enlarged exploded view of the modular distributor of thealternative coffee maker;

FIG. 22 is a fragmentary top perspective view of the heating chamberinterior of the alternative coffee maker showing the modular distributorproperly installed;

FIG. 23 is a bottom perspective view of the heating chamber of thealternative coffee maker showing the underside of the modulardistributor;

FIG. 24 is an enlarged fragmentary perspective view of the showerheadand centrifugal basket of the alternative coffee maker;

FIG. 25 is a fragmentary cross-sectional view of an alternativeembodiment of the modular distributor;

FIG. 26 is a bottom perspective view of the alternative modulardistributor;

FIG. 27 is a top fragmentary perspective view of the alternative modulardistributor shown installed within the heating chamber;

FIG. 28 is a schematic of the water flow into the basket.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

I. Overview

Referring to FIG. 1, there is illustrated a preferred embodiment of acoffee maker 10 including a counter top unit 20 and at least one carafe22.

The counter top unit 20 has front and rear sides 24 and 26, a base 28,lower and upper portions 30 and 32, and a removable lid 34. Thecountertop unit 20 is comprised of a housing 50, a water heating system52, a brewing assembly 54, a collection system 56, and a control system58.

As seen in FIGS. 2-4, the water heating system 52 is positioned at therear 26 of the counter top unit 20. The water heating system 52comprises a funnel region 60, a storage tank 62, a water flow pipe 64,and a heating element 66. A large open space located directly under thelid 34 forms the funnel region 60. This region 60 receives the brewwater when it is initially poured into the unit 20 by a user. The funnelregion 60 is in fluid communication with the storage tank 62. Thestorage tank 62 has a bottom 68 and sides 70 extending upwardlytherefrom and is preferably formed of plastic. An aperture (not shown)through which the water exits the storage tank 62 is defined by thebottom 68. The water flow pipe 64, which has an inflow and an outflowportion 72 and 74 and a heating portion 76, is attached by the inflowportion 72 to the storage tank 62 at the aperture. The inflow portion 72is also preferably formed of plastic. A valve (not shown), preferably acheck valve, is positioned in the inflow portion 72 and controls theflow of water out of the storage tank 62 and into the flow pipe 64.Preferably, the valve does not regulate the rate of flow of water out ofthe tank 62 but allows water to flow freely; the valve does, however,prevent any backflow of water into the storage tank 62.

The heating portion 76 of the flow pipe 64 forms a general U-shape onthe rear 26 of the counter top unit 20. The heating element 66 is alsoformed in a general U-shape and is adjacent to the heating portion 76.Both the heating element 66 and the heating portion 76 of the flow pipe64 are preferably manufactured of aluminum to facilitate heat transfer.The outflow portion 74 of the flow pipe 64 extends from the heatingportion 76 and is preferably manufactured of silicone to withstand theelevated temperature of the brew water after it passes through theheating portion 76.

Referring now to FIGS. 5-8, the brewing assembly 54 comprises ashowerhead 78, a basket assembly 80, and a drive system 82. Theshowerhead 78, as seen in FIG. 5, has upper and lower ends 84 and 86,the upper end 84 attached to and in fluid communication with the outflowend 74 of the flow pipe 64 to receive the heated brew water. Theshowerhead 78, which is trough-shaped, is located directly below theremovable lid 34 for ease of access and extends upwardly into the funnelregion 60. A cap 88 mounts in a snap-fit manner over the trough tominimize overflow of the heated water from the showerhead 78. However,if the water overflows the trough, it escapes under the cap 88 andoverflows into the funnel region 60, from which it flows back into thestorage tank 62. Additionally, the cap 88 is removable by a user tofacilitate cleaning of the showerhead 78 to prevent lime accumulation.The showerhead 78 is angled downwardly to allow water to flow towardsits lower end 86. Located in the lower end 86 of the showerhead 78 are aplurality of apertures 90 spaced radially outwardly from the center ofthe brewing assembly 54 for distributing the heated water over thecoffee grounds.

As seen in FIG. 6, the basket assembly 80 is positioned under theshowerhead 78. The basket assembly 80 is comprised of a centrifugalbasket 92 and a stationary collection basket 94. Centrifugal basket 92rotates within stationary collection basket 94 during the brewing cycle.

As seen in FIGS. 6-8, the centrifugal basket 92 has a bottom 96 andangled sides 98 extending upwardly therefrom, the sides 98 having upperand lower edges 100 and 102. Extending outwardly from the upper edge 100of the sides 98 is a basket rim 104. The sides 98 include a plurality ofcircumferentially-spaced, vertically-extending side ports 106 throughwhich the brewed coffee exits the centrifugal basket 92. The ports 106extend to the lower edge 102 of the sides 98 to allow the brewed coffeeto easily exit the basket 92.

The basket 92 preferably is operated at an angular velocity of 100-150rpm, and most preferably at 130 rpm. At this angular velocity, thegrounds and water slurry does not escape above upper edge 100. Thebasket 92 preferably has a radius of 2.25 inches at a point on the loweredge 102 of the side walls 98. At this lower velocity, the water is incontact with the grounds for a sufficient time to fully extract theflavor before exiting the basket 92 through the vertical ports 106.Additionally, the basket 92 is spinning sufficiently to move the waterradially through the grounds towards the side walls 98 and the verticalports 106. The slurry achieves an equilibrium profile which does notallow the slurry to reach upper edge 100.

As seen most clearly in FIG. 6, the collection basket 94 also includes abottom 110 and upwardly extending sides 112. The collection basket 94 ishingedly attached to the housing 50 of the coffee maker unit 20,allowing it and the nested centrifugal basket 92 to swing away from thecoffee maker unit 20 for a user to insert a filter and coffee groundsinto the centrifugal basket 92. The bottom 110 of the collection basket94 includes a central spindle 114 extending upwardly and two ports (notshown) through which the coffee exits the basket assembly 80. The bottom96 of the centrifugal basket 92 interfits with the spindle 114 (as seenmost clearly in FIG. 12), as seen most clearly in FIGS. 6 and 8, torotatably secure the centrifugal basket 92 to the collection basket 94.

Referring now to FIGS. 9 and 10, the brewing assembly 54 furtherincludes drive system 82. The drive system 82 includes a drive motor 120having upper and lower portions 122 and 124 located within the housing50 and positioned adjacent the basket assembly 80 (as seen in FIG. 6).Extending from the upper portion 122 of the drive motor 120 is arotatable drive shaft 126 fitted with an O-ring 128 on its free end 130.As seen in FIG. 10, when the centrifugal and collection baskets 92 and94 are positioned within the coffee maker unit 20, the O-ring 128 restsupon the rim 104 of the centrifugal basket 92. The drive motor 120 turnsthe shaft 126 which, in turn, rotates the O-ring 128 and spins thecentrifugal basket 92. Extending from the lower portion 124 of the drivemotor 120 is a spring-loaded plunger 132 which, when the collection andcentrifugal baskets 92 and 94 are positioned within the coffee makerunit 20, contacts the collection basket 94. The drive motor 120 issuspended within the housing 50 by two pins 133, as seen most clearly inFIG. 6, about which the drive motor 120 may pivot. When the basketassembly 80 is within the coffee maker unit 20 and contacting theplunger 132, the plunger 132, from its spring actuation, absorbs aportion of the force from the basket assembly 80; the remainder of theforce pushes the plunger 132 linearly, thus pivoting the drive motor120. The shaft 126 and O-ring 128 then rotate downwardly, positioningthe O-ring 128 against the rim 104 of the centrifugal basket 92. Theplunger's absorption of a portion of the forces as a result of itsspring-loading allows the O-ring 128 to rest on the rim 104 with minimaldownward pressure.

Referring now to FIGS. 11-13, the coffee maker 10 further includes acollection system 56 comprised of two carafes, a glass or plastic carafe150 and a thermal carafe 152. Both carafes 150 and 152 fit individuallywithin a carafe cavity 154 of the coffee maker unit 20; the carafecavity has a bottom 156 and upwardly extending sides 158. A carafeheating plate 160 forms the bottom 156 of the cavity 154, and bothcarafes 150 and 152 rest upon the heating plate 160 when either iswithin the cavity 154. A rectangular shaped heating element 161 isdisposed beneath heating plate 160 to supply heat to heating plate 160and the carafe resting on the heating plate 160. One side 162 of thecavity 154 defines an aperture 164 through which a carafe sensor 166extends into the cavity 154. The sensor 166 is preferably comprised of aspring-actuated plunger 168 having a shaft 170 and a contact end 172.The plunger 168 includes a ramp 174 extending from the shaft 170 which,as the plunger 168 retracts within the wall 162 of the carafe cavity154, contacts a switch 176 to activate the heating element 161.

As seen most clearly in FIG. 11, the thermal carafe 152 and the glasscarafe 150 are provided with differing profiles. Each of the carafes 152and 154 contacts the contact end 172 of the plunger 168 when it isplaced within the carafe cavity 154; however, each carafe 152 and 154,due to their differing profiles, displaces the plunger 168 a differentdistance. As seen in FIG. 12, the glass carafe 150, having the smallerprofile, displaces the plunger 168 a smaller distance than does thethermal carafe 152. When the glass carafe 150 is placed within thecarafe cavity 154, it displaces the plunger 168 so that the ramp 174 isin contact with the switch 176, and the heating element 161 isactivated. However, as seen in FIG. 13, when the thermal carafe 152 isplaced within the carafe cavity 154, the plunger 168 is displaced agreater distance so that the ramp 174 is not in contact with the switch176, and, thus, the heating element 161 is not activated. The ramp 174briefly contacts the switch 176 as the plunger 168 is displaced by thethermal carafe 152; however, this momentary contact is insufficient toactivate the heating element 161.

As seen in FIG. 14, the coffee maker 10 further includes control system58. The system 58 has a manually operated start button 200 located onthe housing 50 of the counter top unit 20. The system 58 furtherincludes a microprocessor 202 in electrical connection with a powerboard204, water heating controls 206, motor controls 208, and maintenanceheating controls 210. The water heating controls 206 include anelectrical connection 212 between the heating element 66 and thepowerboard 204 to control activation of the heating element 66. Themicroprocessor 202 directs power to the heating element 66 for the firstseven seconds of the brew cycle, then deactivates the element 66 foreight seconds, allowing time for heat transfer from the heated water tothe downstream unheated water. Then the microprocessor 202 switches theheating element 66 back on. A thermistor 214 is positioned adjacent tothe heating element 66 to monitor the temperature of the element 66;drastic temperature increases in the heating element 66 indicate that nobrew water is present in the flow pipe 64 to absorb the heat from theelement 66. When the thermistor 214 detects such a temperature increase,the microprocessor 202 cuts the power to the heating element 66, and thebrew cycle ends.

The motor control 208 comprises an electrical connection 216 between thedrive motor 120 and the powerboard 204 to control activation of themotor 120. The microprocessor 202 directs power to the motor 120 to spinthe centrifugal basket 92. The motor 120 is activated after the eightsecond deactivation of the heating element 66 and continues spinning forthe remainder of the brew cycle. Immediately after the brew cycle, thebasket 92 is spun an additional twenty seconds at an accelerated speed,known as the “dry spin,” to extract the remaining coffee from the waterand grounds slurry. Then the microprocessor 202 cuts all power to thedrive motor 120.

The maintenance heating control 210 comprises an electrical connection218 between the switch 176 and the microprocessor 202 and an electricalconnection 220 between the heating element 161 and the powerboard 204.The microprocessor 202 monitors the switch 176 for at least five secondsof activation. Thus, the momentary activation caused by the insertion ofthe thermal carafe 152 into the cavity 154 is ignored by themicroprocessor 202. After five seconds of activation, the microprocessor202 directs power from the powerboard 204 to the heating element 161 tomaintain the coffee temperature in the glass carafe 150. The heatingsurface 160 remains activated for two hours after completion of the brewcycle unless the element 161 is deactivated by removal of the glasscarafe 150 or until the coffee maker 10 is turned off. Themicroprocessor 202 cuts power to the heating element 161 if the glasscarafe 150 is removed from the cavity 154; however, if the carafe 150 isreturned to the cavity 154 within the two hour period, the heatingelement 161 is reactivated.

An alternative embodiment of the coffee maker 300 is seen in FIG. 15.The alternative embodiment 300 comprises a countertop unit 302 havingtop and bottom portions 304 and 306. The counter top unit 302 includes abatch water heating system 308, a basket assembly 309, and a controlsystem 311.

As seen in FIGS. 16-18, the batch heating system 308 is positioned atthe top 304 of the counter top unit 302. Within the water heating system308, there is a water heating chamber 310 having a bottom 312 andsubstantially vertical sides 314 extending upwardly therefrom and adistributor 316. A valve (not shown) controls the flow of water out ofthe water heating chamber 310 and is positioned on the bottom of thechamber 312, the valve being controlled by a solenoid or bimetal. Thedistributor 316 also is positioned on the bottom 312 of the waterheating chamber 310. Distributor 316 controls the water flow rate out ofthe chamber 310. Preferably, the distributor 316 rests upon the valve.

As seen in FIGS. 19-23, the distributor 316 preferably mounts to thewater heating chamber 310 using a bayonet mount. Distributor 316 has atop 318 and a bottom 320 and two wings 322 located on its top 318. Thewings 322 allow a user to insert the distributor 316 and twist it, whichlocks the distributor 316 in place in water heating chamber 310. Thebottom 320 of the distributor 316 has two protruding flanges 324 which,as the distributor 316 is set in place, fit under a washer 326 to securethe distributor 316 to the bottom 320 of the water heating chamber 310;as the distributor 316 is turned clockwise, the flanges 324 lock inplace. Turning the distributor 316 counter-clockwise releases theflanges 324 and allows the distributor 316 to be removed. Thedistributor 316 also has a single central aperture 328 through whichwater may flow out of the water heating chamber 310. The distributor 316is designed for easy removal, thus allowing for cleaning or replacementas lime accumulates on the distributor 316.

The distributor 316 is preferably constructed of a plastic, such asUltem™ (a trademark of general Electric Corp.), treated to withstand thehigh temperatures present in the heating chamber 310. Other materials,including a coated metal, may also be used in constructing thedistributor 316.

Referring now to FIG. 24, the basket assembly 309 includes a showerhead340 and nested centrifugal and collection baskets 342 and 344. Theshowerhead 340 is trough-shaped and has upper and lower ends 346 and348. The upper end 346 of the showerhead 340 is located directly underthe distributor 316 and the valve to receive the heated water as itflows from the heating chamber 310. The showerhead 340 is angled withits upper end 346 positioned higher than its lower end 348, thusallowing the heated water to flow by gravity towards its lower end 348which extends radially towards the side of the centrifugal basket 342.The showerhead 340 defines a plurality of apertures 350 along itslength. The apertures 350 must be spaced from each other, although theamount of spacing may be varied. Additionally, the apertures 350 may beuniform or varied in size. As water flows out of the water heatingchamber 310 and through the distributor 316, it lands on the upper end346 of the showerhead 340. Water flows towards the lower end 348 of theshowerhead 340 and through the apertures 350 into the centrifugal basket342. Further, the showerhead 340 has a front side 352 and a rear side354; the showerhead 340 is preferably inclined so that the front side352 is higher than the rear side 354. Alternatively, the showerhead 340may be held level.

The showerhead 340 is designed for easy removal to facilitate cleaningor replacement. The showerhead 340 is preferably constructed of plastic.However, other materials which are approved for contact with humanconsumables and can withstand brewing temperatures may also be used.

The counter top unit 302 further includes a control system 311 having astart button 360. The start button 360, which is manually operated, islocated on the counter top unit 302. The control system 311 activates aheater (not shown) to heat the water in the chamber 310 to 195°-205°Fahrenheit then deactivates the heater. The control system 311 activatesa drive motor 362 to spin the centrifugal basket 342, and then after aten second delay, a solenoid or temperature sensitive bimetal disc opensthe valve to allow water to flow out of the water heating chamber 310.The control system 311 monitors the volume of water in the chamber 310;once the chamber 310 is empty, the solenoid valve is closed by thecontrol system 311 or the bimetal disc resets itself, and thecentrifugal basket 342 is stopped after a fifteen second delay.

Referring to FIGS. 25-27, a second alternative embodiment of thisinvention includes an alternative distributor 370 for the batch waterheating system 308. The alternative distributor 370 further controls theflow of water. It has two flow holes 372 and 374, a horizontal flow hole372 and a vertical flow hole 374. Additionally, the distributor 370 hasa needle valve (not shown) located within the flow holes 372 and 374.Securement of the alternative distributer 370 is accomplished using abayonet type mount.

II. Assembly and Operation

An improved brewing process using a coffee maker made in accordance withthis invention will now be described. The basket assembly 80 is manuallyswung away from the coffee maker unit 20 and a coffee filter positionedin the centrifugal basket 92. Up to 100 grams of coffee grounds areadded to the basket 92. The basket assembly 80 is swung back intoposition within the housing 50, and the collection basket 94 contactsthe spring-loaded plunger 132, pushing the plunger 132 and rotating thedrive motor 120 about the pins. The shaft 126 swings downwardly, and theO-ring 128 rests on the rim 104 of the centrifugal basket 92.

Water is manually poured into the funnel region 60 of the heating system52 and flows into the storage tank 62 and flow pipe 64, a portion of thewater flowing past the heating portion 76 of the flow pipe 64. The startbutton 200 is pushed by the user to initiate the brewing process, andthe water heating element 66 is activated for an initial seven seconds.This is sufficient time to heat the water in the heating portion 76 ofthe flow pipe 64 preferably to between 195-205° Fahrenheit. The heatingelement 66 is then deactivated for eight seconds. During this time, heattransfer occurs between the heated portion of water within the heatingportion 76 of the flow pipe 64 and the unheated portion in thedownstream portion of the pipe 64. As the heating element 66 isdeactivated, the microprocessor 202 directs power to the drive motor 120to begin spinning the basket 92 and to the heating element 161 if theglass carafe 150 is within the carafe cavity 154.

The heating element 66 is re-activated for the remainder of the brewingcycle. Water in the heating portion 76 of the flow pipe 64 is heated bythe heating element 66 until it exceeds 212° Fahrenheit and vaporizes toexpand within the flow pipe 64. Due to the presence of the check valvebetween the flow pipe 64 and the water storage tank 62, the water vaporexpands into the downstream portion of the flow pipe 64. The first batchof water vapor, which corresponds to the water present in the heatingportion 76 of the flow pipe 64, pushes the non-vaporized, yet heated,water before it through the pipe 64. As the water vapor loses contactwith the heating element 66, ideally it cools to 195-205° Fahrenheit andcondenses. The brew water continues to flow through the pipe 64,vaporizing then condensing after it passes through the heating portion76. The condensed water flows from the outflow portion 74 of the flowpipe 64 into the showerhead 78. By gravity, the water flows toward thelower end 86 of the showerhead 78 and passes through the plurality ofapertures 90. As schematically shown in FIG. 28, the coffee slurry formsa generally concave profile with respect to the outer sloped basketwalls 98. Accordingly, the radial thickness of the coffee slurry at agiven height from the basket bottom 96 decreases from the bottom to thetop. Therefore, more water is allowed to fall to the center of thebasket 96 as compared to the side where the radial thickness of theslurry is less.

The heated brew water falls upon coffee grounds held in the spinningcentrifugal basket 92. The basket 92 is preferably spinning at 130 rpm,which prevents overflow of the grounds and water slurry. As the basket92 spins, distinct annular areas of wet grounds are formed. The watertravels radially outward due to the spinning of the centrifugal basket92, wetting all of the grounds. Thus, the water is generally uniformlydistributed through the coffee grounds with each of the groundsreceiving approximately the same exposure to the water during thebrewing process. The coffee escapes the centrifugal basket 92 throughthe vertical ports 106 which extend to the bottom edge 102 of the sides98 of the basket 92. Extending the ports 106 to the bottom edge 102allows the coffee to escape the basket 92 without requiring that thecoffee reach some opening at a predetermined height above the bottom ofthe basket 92, as required by other coffee makers, while providing anideal extraction of coffee from the grounds. Thus, the basket 92 mayrotate at a slower speed, minimizing the amount of slurry and coffeegrounds which overflow the basket 92.

As the coffee passes though the vertical ports 106, it falls into thecollection basket 94 and flows down its side walls 112. The coffeepasses out of the basket through the bottom ports.

The carafe, either glass or thermal 150 or 152, sets on the heatingsurface 160 within the carafe cavity 154 directly below the ports andreceives the brewed coffee. If the glass carafe 150 is within the cavity154, the plunger 168 is displaced so that the ramp 174 is in contactwith the switch 176. After the required delay, the microprocessor 202directs power to the heating element 161. However, if the thermal carafe152 is within the carafe cavity 154, the plunger 168 is displaced agreater distance, and the ramp 174 does not maintain contact with theswitch 176 for the required activation time period.

The water heating system 206 monitors the amount of water remaining inthe flow pipe 64. As the thermistor 214 detects a rise in thetemperature of the heating element 66, the microprocessor 202deactivates the element 66 to end the brew cycle. The centrifugal basket92 is spun at a higher speed for twenty seconds to extract the remainderof the coffee. The remaining portion passes through the vertical ports106, into the collection basket 94, and thence into the carafe 150 or152. If the glass carafe 150 is within the carafe cavity 154, theheating element 161 remains activated for two hours after the brew cycleends unless the coffee maker 10 is switched off or the carafe 150 isremoved from the cavity 154.

The improved brewing process using the alternative coffee maker 300 willnow be described. Water is manually poured into the heating chamber 310,and the start button 360 is pushed by the user to initiate heating.Water is heated to, and maintained at preferably 195-205° Fahrenheit.Feedback controls 311 indicate when the preferred temperature range isreached, and then drive motor 362 begins spinning centrifugal basket 342holding coffee grounds. A solenoid/bimetal then opens a valve in thebottom 312 of the heating chamber 310 to allow the heated water to flowout of the heating chamber 310.

The modular distributor 316 regulates the flow of the heated water outof the heating chamber 310. After water passes through the distributor316, it lands on the showerhead 340. The trough-shaped showerhead 340catches the heated water and channels it through the plurality ofapertures 350. The brew water falls upon coffee grounds held in thecentrifugal basket 342. The centrifugal basket 342 spins as the waterfalls on the coffee grounds, creating distinct annular areas of wetgrounds. The water then travels radially outward due to the spinning ofthe centrifugal basket 342, wetting all of the grounds. Thus, the wateris generally uniformly distributed through the coffee with each of thegrounds receiving approximately the same exposure to the water duringthe brewing process.

The water passes through the coffee grounds, exits the centrifugalbasket 342 and flows into the collection basket 344. The coffee is thenfunneled from the collection basket 344 into a carafe.

If the alternative modular distributor 370 is used, the flow of wateronto the showerhead 340 is further regulated. This alternativedistributor 370 allows four cups of coffee to be brewed in four minutesor four to ten cups of coffee to be brewed in four to six minutes. Thealternative distributor 370 includes two orifices 372 and 374 throughwhich water may flow. If only four cups of water are placed in theheating chamber 310, the water flows through only one orifice, thehorizontal flow hole 372. If more than four cups of water are used, thewater also flows through the vertical flow hole 374; utilizing the twoflow holes 372 and 374 decreases the overall time for brewing severalcups of coffee. A needle valve, located in the flow holes 372 and 374,breaks up the surface tension of the water to create a flow of smallerdroplets. This alternative distributor 370 includes a bayonet mount foreasy removal. Hence, the distributor 370 may be easily cleaned orreplaced if lime buildup is a problem.

The above descriptions are those of preferred embodiments of theinvention. Various alterations and changes can be made without departingfrom the spirit and broader aspects of the invention as defined in theappended claims, which are to be interpreted in accordance with theprinciples of patent law including the Doctrine of Equivalents.

The embodiment of the claims in which an exclusive property or privilegeis claimed are defined as follows:
 1. A coffee maker, comprising: acarafe support means for supporting a single carafe; a heating means forheating coffee within a carafe supported by said support means; athermally insulated carafe; a thermally uninsulated carafe; a detectionmeans for detecting which of the two carafes is supported by saidsupport means; and control means responsive to said detection means toactivate said heating means when said thermally uninsulated carafe issupported by said support means but to not activate said heating meanswhen said thermally insulated carafe is supported by said support means.2. The coffee maker as recited in claim 1 wherein said detection meansincludes a spring-actuated plunger having a first end in physicalcontact with said carafe, said plunger including a ramp, and saidcontrol means including an electrical system having a switch and aprocessor, said ramp contacting said switch when said thermallyuninsulated carafe is supported by said support means, said processormonitoring said switch and activating said heating means when saidthermally uninsulated carafe is supported by said support means.
 3. Acoffee maker, comprising: a heating source for heating a carafe and itscontents; a first carafe; a second carafe; a carafe indicator in contactwith said first or second carafe when said carafe is in contact withsaid heating source, said indicator monitoring which of said first orsecond carafes is in contact with said heating source; and a controlsystem activating said heating source when said first carafe is incontact with said heating source.
 4. A coffee maker, comprising: aheating source for heating a carafe and its contents; a first carafe; asecond carafe; a control system activating said heating source when saidfirst carafe is in contact with said heating source; and a carafeindicator in contact with said first or second carafe when said carafeis in contact with said heating source, said indicator monitoring whichof said first or second carafes is in contact with said heating sourcewherein said carafe indicator comprises: a spring-actuated plungerincluding a ramp; and wherein said control system comprises: a switchand a processor, said ramp contacting said switch when said first carafeis in contact with said heat source, said processor monitoring saidswitch, and said processor activating said heat source when said firstcarafe is in contact with said heat source.
 5. A coffee makercomprising: a first carafe including a first means for identifying saidfirst carafe; a second carafe including a second means for identifyingsaid second carafe; means for supporting one of said first and saidsecond carafes; means for heating said one carafe; means for sensing oneof said first identifying means and said second identifying means whensaid one carafe is on said support means; and means responsive to saidsensing means for selectively activating said heating means when saidone carafe is on said support means, wherein said responsive meansactivates said heating means when said first identifying means is sensedby said sensing means and does not activate said heating means when saidsecond identifying means is sensed by said sensing means.
 6. The coffeemaker of claim 5 wherein said first identifying means is a profile ofsaid first carafe and said second identifying means is a profile of saidsecond carafe.
 7. The coffee maker of claim 6 wherein said respondingmeans comprises: a plunger capable of contacting one of said first andsecond carafes when said one carafe is disposed on said supportingmeans; a switch in electrical communication with a processor, saidswitch actuatable by said plunger when said one carafe is supported bysaid support means, said processor capable of detecting the actuation ofsaid switch whereby said processor activates said heating means.
 8. Thecoffee maker of claim 7 wherein said plunger is coupled to a ramp forcontacting said switch when said first carafe is supported by saidsupport means.
 9. A method for differentiating between first and secondcarafes used in conjunction with a coffee maker comprising: providing afirst carafe and a second carafe, the first carafe including a firststructural identifying characteristic, the second carafe including asecond structural identifying characteristic different from said firstidentifying characteristic; supporting one of the first and secondcarafes; detecting one of the first structural identifyingcharacteristic and the second structural identifying characteristicduring said supporting step; and selectively heating the supportedcarafe in response to the detected characteristic.
 10. A method fordifferentiating between first and second carafes used in conjunctionwith a coffee maker comprising: providing a first carafe and a secondcarafe the first carafe including a first identifying characteristic,the second carafe including a second identifying characteristic;supporting one of the first and second carafes; heating one of the firstand second carafes; sensing one of the first identifying characteristicand the second identifying characteristic during said supporting step;and responding to said sensing step to selectively initiate said heatingstep when one of the first and second carafes is supported wherein saidsensing step comprises: placing one of the first and second carafeswithin a cavity defined by the coffee maker; displacing a protrusion inthe cavity; measuring the displacement of the protrusion; andassociating the displacement with one of said first and second carafes.11. The method of claim 10 wherein said heating step is initiated whenthe first identifying characteristic is sensed during said sensing stepand not initiated when said second characteristic is sensed during saidsensing step.
 12. The method of claim 11 wherein the first carafe is anuninsulated carafe and the second carafe is an insulated carafe.